A Simple, Rapid, Sensitive and Eco-Friendly LC-MS/MS Method for Simultaneous Determination of Free Cordycepin and Isocordycepin in 10 Different Kinds of Cordyceps

A simple, rapid, sensitive and eco-friendly liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed for simultaneous determination of free cordycepin (3 '-deoxyadenosine) and isocordycepin (2 '-deoxyadenosine) in 10 kinds of Cordyceps samples. The samples were prepared by ultrasonic extraction at 75 degrees C for 30 min with boiling water as the extraction solvent. The LC separation was performed on an Agilent poroshell 120 SB-Aq C18 column (3.0 x 50 mm, 2.7 mu m) in isocratic mode with an eco-friendly mobile phase (2% ethanol containing 0.2% acetic acid) at a flow rate of 0.6 mL min(-1), and detected by MS/MS in positive mode with multiple reaction monitoring (MRM). The developed method showed good linearity (r > 0.9990), sensitivity (LODs = 0.04 pg, LOQ = 0.1 pg), precision (RSD <= 3.8%) and stability (RSD <= 3.6%). The recoveries of developed method were 94.4-109.5% (RSD <= 5.5%). Compared with reported methods, the current method was rapid (less than 35% analytical time), sensitive (more than 5 folds), and eco-friendly (less than 10 mu L harmful organic solvent). 10 different kinds of Cordyceps samples (40 batches) were tested by the developed method. Codycepin was only found in Cordyceps millitaris and C. millitaris fruiting body, and isocordycepin was detected in Cordyceps sinensis and other 6 Cordyceps samples. The developed method would be an improved method for the quality evaluation of Cordyceps samples.